The sordid past of Kim Richards' new boyfriend

More tears for Kim?

New details have emerged about Kim Richards' controversial new boyfriend, Ken Blumenfeld.

A certain Real Housewife thinks that her sister's new boyfriend is bad business, and she's not keeping quiet about it. Kyle Richards is none too pleased about her older sister Kim Richards' boyfriend Ken Blumenfeld, who happens to have a shady past.

Blumenfeld was arrested in 2009 for a DUI, which is sure to raise yet more concerns for the reality star's own sobriety.

Kim has kept her relationship with Blumenfeld secret for over a year before telling her sister.

According to sources, the younger Richards sister admitted she fears he will be a bad influence, adding that Kim's children consider him to be bad news as well.

"I was so disappointed and worried to be honest," Kyle has said of her sister's decision to move in with Blumenfeld, reports The Daily Mail. "I felt she was making this decision based on convenience and loneliness, which worried me and made me sad. I do not know Ken. I have heard things that put me off, however, if Kim truly is happy, I will support her."

But it's not just Blumenfeld's spotty past (or the fact that he may still be active on an online dating site) that are sending red flags. A source for Radar Online called the man "controlling" and another insider told the Daily Mail that he's"not right" for the reality star.

Adding more fuel to the fire, a source has told The Daily Mail that Blumenfeld is a "nightmare" who has ignited several explosive arguments with Kim at his Westlake home.

Apparently one fiery argument even forced Kim to move out of the home, until Blumenfeld tracked her down at a friend's house and persuaded her to move back in.

The source also adds, "The family doesn't like him, he's controlling and Kim shouldn't be living at his house."

"Kim went through a lot last year with her drinking problem and the pressure from the show and her relationships only trigger Kim's addiction."